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* kworker/0:3+pm hogging CPU
@ 2020-07-20  8:39 Michal Hocko
  2020-07-20 13:58 ` Alan Stern
  0 siblings, 1 reply; 19+ messages in thread
From: Michal Hocko @ 2020-07-20  8:39 UTC (permalink / raw)
  To: LKML, Alan Stern, Greg KH; +Cc: linux-usb, Rafael J. Wysocki

Hi,
I am not sure when this started happening but at least 5.6, 5.7 and
5.8-rc6 all exhibit this problem. Please note that the this is happining
on a laptop which is not completely healthy. The BIOS complains that the
Battery cannot be charged because the power supply cannot be recognized.
This is somehting I have for a longer time without noticing the
kworker/0:3+pm problem so I do not think they are related but who knows.

Anyway, kworker/0:3+pm is hogging CPU. /proc/<pid>/0:3+pm is very often
empty so I suspect it just schedules very often and performs only small
amount of work. Here are few backtraces I've managed to catch

[<0>] preempt_schedule_thunk+0x16/0x18
[<0>] usb_hcd_submit_urb+0x686/0x773
[<0>] usb_start_wait_urb+0x59/0xc8
[<0>] usb_control_msg+0xd4/0x10d
[<0>] get_port_status+0x51/0x6f
[<0>] hub_port_status+0x41/0xa3
[<0>] hub_activate+0x230/0x4ee
[<0>] hub_resume+0x20/0x9a
[<0>] usb_resume_interface.isra.0+0xb0/0xd0
[<0>] usb_suspend_both+0xf6/0x20c
[<0>] usb_runtime_suspend+0x32/0x62
[<0>] __rpm_callback+0x70/0xd4
[<0>] rpm_callback+0x55/0x6b
[<0>] rpm_suspend+0x2af/0x440
[<0>] __pm_runtime_suspend+0x48/0x62
[<0>] usb_runtime_idle+0x26/0x2d
[<0>] __rpm_callback+0x70/0xd4
[<0>] rpm_idle+0x179/0x1df
[<0>] pm_runtime_work+0x6b/0x81
[<0>] process_one_work+0x1bd/0x2c6
[<0>] worker_thread+0x19c/0x240
[<0>] kthread+0x11b/0x123
[<0>] ret_from_fork+0x22/0x30

[<0>] slab_pre_alloc_hook+0x15/0x46
[<0>] __kmalloc+0x148/0x15a
[<0>] usb_hcd_submit_urb+0x5c6/0x773
[<0>] usb_start_wait_urb+0x59/0xc8
[<0>] usb_control_msg+0xd4/0x10d
[<0>] get_port_status+0x51/0x6f
[<0>] hub_port_status+0x41/0xa3
[<0>] hub_activate+0x230/0x4ee
[<0>] hub_resume+0x20/0x9a
[<0>] usb_resume_interface.isra.0+0xb0/0xd0
[<0>] usb_suspend_both+0xf6/0x20c

[<0>] slab_pre_alloc_hook+0x15/0x46
[<0>] __kmalloc+0x148/0x15a
[<0>] usb_hcd_submit_urb+0x5c6/0x773
[<0>] usb_start_wait_urb+0x59/0xc8
[<0>] usb_control_msg+0xd4/0x10d
[<0>] set_port_feature+0x33/0x38
[<0>] hub_suspend+0x15c/0x16a
[<0>] usb_suspend_both+0x91/0x20c
[<0>] usb_runtime_suspend+0x32/0x62
[<0>] __rpm_callback+0x70/0xd4
[<0>] rpm_callback+0x55/0x6b
[<0>] rpm_suspend+0x2af/0x440
[<0>] __pm_runtime_suspend+0x48/0x62
[<0>] usb_runtime_idle+0x26/0x2d
[<0>] __rpm_callback+0x70/0xd4
[<0>] rpm_idle+0x179/0x1df
[<0>] pm_runtime_work+0x6b/0x81
[<0>] process_one_work+0x1bd/0x2c6
[<0>] worker_thread+0x19c/0x240
[<0>] kthread+0x11b/0x123
[<0>] ret_from_fork+0x22/0x30

Is this something known or something I can give more information about?
From a very quick look into the code it sounds as if the system wanted
to suspend an USB device/controller but that keeps failing again and
again.
-- 
Michal Hocko
SUSE Labs

^ permalink raw reply	[flat|nested] 19+ messages in thread

end of thread, other threads:[~2020-09-04 15:57 UTC | newest]

Thread overview: 19+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-07-20  8:39 kworker/0:3+pm hogging CPU Michal Hocko
2020-07-20 13:58 ` Alan Stern
2020-07-20 14:32   ` Michal Hocko
2020-07-20 15:12     ` Alan Stern
2020-07-20 16:33       ` Michal Hocko
2020-07-20 17:38         ` Alan Stern
2020-07-20 17:45           ` Michal Hocko
2020-07-20 17:48             ` Alan Stern
2020-07-20 18:16               ` Michal Hocko
2020-07-20 20:02                 ` Alan Stern
2020-07-21  5:59                   ` Michal Hocko
2020-07-21 14:33                     ` Alan Stern
2020-07-21 16:00                       ` Michal Hocko
2020-07-21 16:14                         ` Alan Stern
2020-08-29  9:50                       ` Salvatore Bonaccorso
2020-08-29 15:59                         ` Alan Stern
2020-08-31 11:37                           ` Mathias Nyman
2020-09-01 15:27                             ` Michal Hocko
2020-09-04 15:57                               ` Dirk Kostrewa

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